How to upgrade Win Next Starter Retail 32bit To any Win 7 64bit ver

Hello forum.

On my way to downgrade Win10 back to 7, on my Satellite Toshiba U840, found out that my serial number for windows 7 was for Starter Retail version.
That is odd because i remember that my windows 7 was 64bit and supported all of the windows features,
in comparison to what Starter Retail provides. I ran alot of graphic programs on 3 years ago...

Is it possible to upgrade the retail version to any Win 7 64 bit version?

Thank you for your time!

Thanks Layback Bear, for your quick reply.

I've updated my specs for you to see.

Pardon me but I think you misunderstood my question.
I'm certain that I had windows 7 64bit installed before upgraded to win10.
When I decided to downgrade, I have found out that the serial number, used by the store from which i bought the laptop, was that of windows starter retail edition.

With that said, I'm trying to find out if I downgrade to 7 retail (coz I have only that windows version serial number) how did the store upgrade me to a win 7 64bit version.

Thank you for your patience

O.K flipped my comp and found the original Windows serial number sticker

It says I had Win7 Home Prem OM, god knows I I know what that means.
Weird that the ShowKeysPlus stated i had Win Next Retail....

Anyway, Thanks again.
I'll post if I get stuck...